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Singapore, Australia, New Zealand and Switzerland round out top five; the U.S. is ranked 10th

North Korea, Cuba and Zimbabwe ranked the lowest of 177 countries in the 2013 index

Countries ranked on rule of law, regulatory efficiency, limited government and open markets

For the 19th year in a row, the Heritage Foundation, a conservative American think tank, has ranked the city of Hong Kong the freest economy in the world.

Singapore was a close second, however, followed by Australia and New Zealand. Switzerland was ranked fifth. The U.S., which has the world's largest economy, was ranked 10th while mainland China -- the world's second largest economy -- was ranked 136th out of 177 economies on the Index of Economic Freedom, a publication co-sponsored by the Wall Street Journal.

However, the editors of the index noted that the global average, which peaked in 2008, has been in decline. "The global advance toward economic freedom has ground to a halt," the index editors said in a new release.

"In the post-Arab Spring Middle East, some democratically elected governments are adopting totalitarian practices reminiscent of revolutionary Iran or the Taliban," Terry Miller, a director at the Heritage Foundation, wrote in the Wall Street Journal. "Economic freedom can't flourish under the arbitrary rule of authoritarians and despots, and it has declined significantly in Egypt, Tunisia, Algeria and Saudi Arabia, among other countries."

The Index evaluates countries in four broad areas of economic freedom: rule of law, regulatory efficiency, limited government and open markets.

The Most Free Economies 2013

1. Hong Kong

2. Singapore

3. Australia

4. New Zealand

5. Switzerland

6. Canada

7. Chile

8. Mauritius

9. Denmark

10. United States

"Almost all of the most advanced countries lost ground this year," Miller wrote. "Even top-ranked Hong Kong saw its score decline due to increased government spending and higher inflation. The United States, ranked only 10th most free in the world this year, joins Ireland as the only advanced economies to have lost economic freedom five years in a row."

While the aggregate global index declined, the scores improved for 91 countries worldwide and decline for 78, the report noted.